README in desert-0.1.1 vs README in desert-0.2.0

@@ -72,6 +72,18 @@
 You can run your plugin tests/specs like so:
 
   rake desert:testspec:plugins PLUGIN=spiffy
 
 Leaving off the PLUGIN environment variable will cause it to run all the test/specs for
-all installed plugins, which may not be what you want.
\ No newline at end of file
+all installed plugins, which may not be what you want.
+
+== Running Desert tests
+
+Desert is a library that heavily monkey patches Rails. To ensure that Desert works with
+multiple versions of Rails, its tests are run against the supported versions of Rails.
+
+To set up the different supported versions of Rails, run `rake install_dependencies`.
+
+This will clone the Rails git repo and export the supported versions of rails into the
+respective directories.
+
+`rake update_dependencies` will update the clones repo on your machine.